Method and material for repairing shoes



N MATERIAL F K ,SHOES BIN: V v

Patented June 4, 1935 Mn'rHon PA ENT" FFICE j plication January 10,

No'Di-awing. Original application September 29, (1931, 881131 NO. 5655922. Divided and this '31) 1933, S erial No. 651,062

1 Claim. (Grist-1'1) This invention relates to a process of repairing worn shoes and similar articles. Theinvention likewise relates to products adapted to be used in the repairing of worn shoes.

This application is divisional of application ilgrial No. 565,922 filed by us on September 29,

The object of the invention is to provide a process and products by which the ordinary individual may repair his or her worn shoes without the employment of special technical skill and without the use of apparatus or equipment or facilities not readily at hand in the ordinary home.

The invention comprises three steps, the first of which is to roughen the sole of the shoe somewhat, the second of which is to apply an adhesive liquid coating to the roughened sole, and the third of which is to apply a plastic moldable, workable material to the adhesive liquid coating to build or reconstitute the sole to the desired thickness and proportions. The heel of the shoe may, of course, be similarly repaired.

From the point of view of marketing the process and products to the public, it is necessary to provide liquid coating compositions and plastic materials which do not harden in the containers in which they are marketed. For the purpose of providing a strong, new shoe sole it is requisite that the plastic material harden very materially when applied to the shoe. The invention may therefore be said to reside in the discovery and determination that a liquid coating composition comprising rubber cement and an accelerator of vulcanization, but no sulfur, and a plastic material comprising rubber and sulfur, but no accelerator of vulcanization, constitutes a combination possessed of the necessary properties specified above.

The rubber cement does not harden in the container because no sulfur is present. The plastic material does not harden or vulcanize in the container due to the absence of an accelerator of vulcanization. When, however, the rubber cement with the accelerator in it is applied to the shoe, and the plastic material containing rubber and sulfur placed over it, a gradual migration of the vulcanization accelerator takes place which causes a progressive vulcanization of the new sole constituted by the plastic material at ordinary room temperature without the use of molds or heat.

In practice the shoe sole is roughened and two coatings of the liquid rubber cement applied. When the second coating becomes tacky, the plastic material containng the rubber is molded over the rubber cement either with a knife or V with the fingers. After standing overnight, the new sole is sufficiently hardened to permit the wearing of the shoes. Further hardening takes place over a period of several days.

In the plastic material it is usually desirable to incorporate fibers, fillers, rubber tougheners, and other ingredients frequently used in the compounding of rubber products. A wide latitude of selection of materials responsive to this invention is therefore possible. Recommended rubber tougheners comprise zinc oxide and carbon black. A rubber solvent such as benzol is preferably used in the plastic to render it appropriately workable. Asbestos is a very appropriate fiber, though other types of fiber may be selected. The filler may be clay dust or Portland cement, or any analogous finely divided material.

The vulcanization accelerators used in the rubber cement may be tetra-methyl-thiuram-disulfide; also tetra-methyl-thiurammonosulfide, dithio-carbamates, such as zinc-di-methyl-di-thiocarbamate, lead-di-methyl-di-thio carbamate, or di-phenyl-guanidine. The selection of the particular accelerator in regard to the selection of the ingredients for the plastic is within the skill of the art.

One example responsive to this invention is as follows:

Formula. for plastic Rubber '70 pounds Asbestos 100 pounds. Portland cement 100 pounds Rosin 1 pound Sulfur '7 pounds Zinc oxide '7 pounds Carbon black 5' pounds Stearic acid 1.5 pounds Benzol 40 gallons In compounding this mixture, all the dry ingredients except the rubber are placed in the mixer with sufficient benzol to wet them thoroughly, and the mixer is run for fifteen Formula for cement Rubber 6 pounds Rosin 2.5 pounds Benzol 15 gallons Zinc-di-methyl-di-thio-carbamate (or other ultra-accelerators) These ingredients are added to thebenzol and stirred until the rubber is dissolved. Two coats of this cement are applied to the roughened shoe sole and allowed to dry. The plastic is then applied about one-fourth inch thick and allowed to dry overnight. The shoes may then be worn, but may not reach their final and complete cure for two more days.

The plastic or workable qualities of the plastic 1.5 pounds material above described, or other plastic materials responsive to this invention, may be further increased by the addition to the admixture of materials such as ethyl or methyl alcohol, isopropyl alcohol acetones or other ketones or alcohols comprising as a class materials which are not solvents for rubber but which are admixable with benzol or the rubber solvent selected for practicing the invention. As an example, 25 pounds of ethyl alcohol of about 90-95% strength may be added to the above specified admixture and the plastic or workable qualities of the material are thereby improved.

I Having described our invention, we desire to be limited. only by the ensuing claim:

'A liquid adhesive adapted to vulcanize and firmly and durably secure a plastic rubber composition containing sulfur to a leather-like surface, said adhesive, com'prising, 6 pounds crepe rubber, 2.5 pounds rosin, and 1.5 pounds zinc dimethyl dithio carbamate, said components fluidified in 15 gallons of benzol.

' ROLAND R. BQLLMAN.

CONRAD L. ORNES. 

